Springer Online Journal Archives 1860-2000
Chemistry and Pharmacology
Abstract Tentoxin[cyclo-(MeAla1-Leu2-MeΔPhe3-Gly4] is a metabolite isolated from a phytopathogenic fungusAlternaria alternata, which induces chlorosis of many plants. This potentialnatural herbicide binds specifically to the soluble part CF1of the chloroplastic coupling factor, which is a proton ATP-synthase. Theeffect of the toxin is concentration dependent: at low concentration it is apowerful inhibitor, while at higher concentration, it stimulates the enzyme.We synthesized tentoxin and we designed new analogues in order to vary thehydrophobicity on the side chain and to study the structure activityrelationships. Comparative activities suggest that it is possible toseparate inhibitory and activating effects using tentoxin analogues, showingsome evidence for the existence of two binding sites with different affinityconstant.
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